Apparatus for controlling the translational and rotational movements of a rod



Feb. 7, 1967 oR 3,302,469

APPARATUS FOR CONTROLLING THE TRANSLATIONAL AND ROTATIONAL MOVEMENTS OFA ROD Filed 001}. la, 1.955

United States Patent 3,302,469 APPARATUS FUR CGNTRDLLIN'G THE TRANSLA-TEONAL AND ROTATIONAL MOVEMENTS OF A RQD Aurelio Urtelli, Bologna,Italy, assignor to S.p.A. Alessandro Calzoni, Via Emilia Ionente, Italy,a company of Italy I iled 0st. 18, 1965, Ser. No. 497,418 Claimspriority, application Italy, Oct. 30, 1964, 23,361/64 6 Elairns. (CI.7422) This invention relates to a device for controlling thetranslational and rotational movements of a rod, and more particularlysaid device comprises means capable of signalling when said rod ispositioned in either end-of-stroke position of its translational stroke.

An object of this invention is to provide a device of the kind referredto above, which is compact and selfcontained within an outer closedshell, without any external members or rods having a notable bulk in theaxial direction which often are affected by severe drawbacks in view oftheir exacting space requirements and which are particularly open toobjection whenever it is desired to provide an efficient hydraulicsealtightness.

Another object is to provide a device in which said means adapted tosignal the end-of-stroke positioning of said rod as regards itstranslational stroke form an integral unit with the means forcontrolling the rotation of the rod, by exploiting constructionalcomponents common to both control means.

Still another object is to provide a device having a minimum size and inwhich the movable members are protected and capable of being readilylubricated.

Yet another object is to arrange said signalling means in such a waythat they comprise a member capable of being displaced through a shortpath, in either direction, beyond an intermediate position responsive tothe fact that the rod is in either end-of-stroke position on completionof a translational travel, even of a considerable length.

The present device comprises a body having a cylindrical straightlinearbore a piston solidly affixed to a rod and positioned within said boreso as to be freely and rectilinearly displaceable therethrough androtatable about its own axis with respect to said body, said rodprojecting out of said body, the body, in correspondence with the pointat which the rod comes out thereof, is fitted with sealtight meansbetween said body and said rod, a shaft housed along a certain portionof its length within a cavity axially formed through said piston andsaid rod, sealtight means between said shaft and said rod, means adaptedto lock said rod and shaft against mutual rotation yet permitting mutualaxial displacements therebetween, means adapted to feed a pressurizedfluid above and below said piston respectively, means to impart arotational drive to said shaft, with the shaft projecting out of saidbody on the side away from that from which said rod protrudes and beingmounted within said body so as to move freely in an axial direction bysmall incremental movements about an intermediate position and theportion of the shaft housed within said cavity of said rod beingprovided with abutments with which said rod interacts when thrust bysaid pressurized fluid towards the maximum elongation position ortowards the minimum elongation position with respect to said body,respectively.

In order that the structure of the: inventive device may be betterunderstood and the advantages stemming therefrom fully appreciated, amerely exemplary and nonlimiting embodiment of said device will be givenhereinafter, reference being had to the accompanying drawing, where-FIGURE 1 is illustrative of a lengthwise cross-sectional view of thedevice,

FIGURE 2 is a cross-sectional view taken along line II-II of FIG. 1, and

FIGURE 3 diagrammatically shows, partly in cross-sectional view, the endportion of the device with a rod, projecting therefrom, which supports aradar head.

Referring to the drawing, it can be seen that the device comprises abody 1 in which a cylindrical bore 2, having a circular cross-section isformed and in which a piston 3, solid with a rod 4 is mounted and thefree end of the rod projects from the body 1 through a bore coaxial withthe bore 2. The latter bore is provided with a bushing 5 and a sealtightring 6. Piston 3 is allowed to rotate freely about its own axis in thebore 2 and be freely translated therein through a stroke whose length isa function of the length of the bore 2. Internally of and coaxially withthe piston 3 and the rod 4 a cavity 7 is formed within which is housed,for a certain portion of its length, a shaft 8. In correspondence withthe piston, tight seals 9 are provided between said piston and the wallof the bore 2 and between the piston and the surface of the shaft 8,respectively. In the wall of the means constituting the cavity 7 areformed two longitudinal grooves 10 within which are housed two noses orkeys 11 projecting from the shaft 8 to which the noses are solidlyaffixed. Due to the shape and mutual positions of the grooves 10 and thenoses 11, the shaft 8 and the rod 4 are allowed to be displaced axiallybut their relative rotation is impeded.

The shaft 8 is extended beneath and out of the piston 3 so as toprotrude for a short distance from the body 1, through a bore formed insaid body under the piston 3 and which is coaxial with the bore 2. Ascan be seen in the lower portion of FIG. 1, the shaft 8 is provided withan integral collar 12 sandwiched between two axially spaced perforateddiscs 13, each of which is urged by a pre-loaded spring 14, biasedbetween an abutment in the body 1 and the disc. The effect of thesprings is to maintain the shaft 8 in an intermediate equilibriumposition. Beneath the springs 14, the shaft 8 has a grooved portion onwhich is mounted a wheel 15 with respect to which the shaft can effectaxial displacements with the wheel being keyed to the shaft to rotatetherewith. The wheel 15 is engaged by a worm 16 which, when is rotatedby a suitable motor (not shown to simplify the showing), causes thewheel 15 and as a consequence the shaft 8 to rotate and, the latter, inturn, transfers the rotational drive to the rod 4 via the noses 11engaging the longitudinal grooves 10. At the end of the portion of shaft8 which projects from the body '1, a graduated disc type dial 17 isaffixed, which, in cooperation with a pointer 18 enables the reading ofthe angle through which the shaft 8 and rod 4 have been rotated withrespect to the body 1. Solidly affixed to said disc-type dial mason tunm is is a second pointer l9 whose position with respect to two axiallyspaced notches 20 and 2% formed about the body 1 indicates whether therod 4 is in its position of full extension or of minimum extension withrespect to the body 1, as will be clarified hereafter.

in the body It a channel 21 is provided which establishes communicationbetween a chamber existing beneath the lower face of the piston and asource of pressurized fluid, more particularly oil, upon actuation ofllow control means which have not been shown for the sake ofsimplification. In substantially the same way, the source of pressurizedfluid is placed in communication, via a channel 22, with a chamberformed above the piston between the outer surface of the rod and thecircular surface of the cylindrical bore 2.

Let us assume now that it is desired to impart a trans lational motionto the rod 4 to displace the rod from the body 1. By admittingpressurized fluid from the channel 2t under the piston 3, said piston isthrust and displaced, non-rotationally, along the bore 2. As the pistonhas been lifted from the position shown in FlG. 1, bottom 23 of thecavity '7 no longer bears on the head of the shaft 8. The shaft 8 thrustby the springs, is restored to its intermediate position where itremains until such time as the rod 4, thrust by the pressurized fluid,has reached its top dead center position, i.e. the position of maximumextension from the body 1, thus effecting a translational movement whichcan even be of a considerable length. When the rod has reached its topdead center, the noses 11 are contacted and thrust by the end walls ofthe grooves close to the piston. By so doing, the shaft 8 is thrust bythe pressurized fluid in the same direction in which the rod has beendisplaced. The shaft is thus lifted from its intermediate position,causing the length of its section protruding below the body 1 to beincreased, the pointer 19 being brought in correspondence with the notch20 thus indicating that the rod has reached its top dead center.

As can be readily seen, the pointer 19 effects a very slightdisplacement from its intermediate position to indicate that the rod hasreached its top dead center, irrespective of the length of the rodsstroke.

lf it is desired to have the rod enter the body It again, no morepressurized fluid is sent to the channel 21, the fluid being converselysent to the channel 22, so as to be operative upon the top of thepiston, the latter being thus thrust towards the position illustrated inFIG. 1. As soon as he piston and the rod have moved from the top deadcenter position, the shaft 8, no longer pressed by said end wall of thegrooves 1d acting on the noses ll,

reverts to its intermediate position, where it remains until such timeas the rod has reached its bottom dead center, i.e. the position shownin FIG. 1, wherein said rod is in the condition of minimum projectionfrom the body 1. Under these conditions, the fluid 23 of the cavity '7presses the head of the shaft 8, which latter is displaced from itsintermediate position bringing the pointer 19 in registry with the notch(FIG. 1) thus signalling a slight displacement indicative of the factthat the rod 4 has reached its bottom dead center.

Assuming now that it is desired to impart a rotational motion to the rod4 about its own axis, irrespective of the fact that the rod is beingtranslated or is at standstill in correspondence with either dead centerposition or in any intermediate position between the dead centers, arotational motion is imparted to the worm 16 which rotates the wheel 15and this, through the shaft 8, the noses 11 and the grooves 10, causesthe rod 4- to be rotated. The angle through which said rod has beenrotated with respect to the body 1 can be read on the dial 17 with thepointer 18.

The fields of application of a device such as described above can benumberless: an example has been shown in FIG. 3 where the device is anintegral part of a radar installation, for example of the collapsibletype, comprising a head 24 containing the electronic components, saidhead being supported by the rod 4 by a double thrust bearing 25 andsolid with a telescopable bar 26 which permits the translation withrespect to the body It but prevents any rotation. The end of the rod 4carries the radar antenna proper 27 which, in addition to being capableof translational movements, must also be capable of rotating oroscillating together with said rod.

The exemplary device illustrated herein is not limiting since it couldbe modified in numerous manners without departing from the scope of theinvention. Thus the rotation control unit comprising the worm gear 1546can be replaced by a hydraulic motor. The indications that the deadcenters have been reached as to the translation of the rod and itsrotation can be derived electrically and transferred to a remote panel.Instead of having the bottom 23 of the cavity 7 abutting the head of theshaft 8 as the rod reaches its bottom dead center, one can have the endwalls of the grooves 10, close to the bottom 23 of the cavity 7,abutting the noses 11: the dial 17 could be dispensed with or also saiddial and the pointer 18 could be replaced by a graduation formed on thesurface of the body 1, whereas the pointer 19, in addition to showingthe attainment of the dead center position, could be used for readingthe angle of rotation upon said gradua tion.

At any rate, the device according to the invention is very compact andwholly contained within the body 1 without any external rod or member,the movable components thus being protected from shocks and theirlubrication convenient. Lastly, to indicate that the rod has reached itsdead centers, the shaft 8 undergoes a slight axial displacement withoutoccupying a large space.

I claim:

1. A device for controlling the translational and rotational movementsof a rod; comprising a body having a cylindrical straightlinear bore, arod, a piston, solidly ai'iixed to said rod and positioned within saidbore so as to be freely and rectilinearly displaceable therethrough androtatable about its own axis with respect to said body, said rodprojecting out of said body, sealtight means bctween said body and saidrod, at the point at which the rod projects from said body, a shafthoused along a certain portion of its length within a cavity axiallyformed through said piston and said rod, sealtight means between saidshaft and said rod, means for locking said rod and shaft against mutualrotation yet permitting mutual axial displacements therebetween, meansfor feeding a pressurized fluid above and below said piston,respectively, means for imparting a rotational drive to said shaft, saidshaft projecting from said body at the end remote from that throughwhich said rod projects, means mounting said shaft within said body soas freely to move in an axial direction by small incremental movementsfrom an intermediate position, and abutments cooperable with saidcertain portion of said shank housed within said cavity when thrust bysaid pressurized fluid towards the maximum elongation position or,respectively, towards the minimum elongation position with respect tosaid body.

2. The device according to claim it, wherein means for indicating theposition of the shaft with respect to the body are provided at the endof said shaft projecting from said body.

3. The device according to claim 1, wherein said cavity formed axiallyin the piston and in the rod is provided with, at least incorrespondence said rod, with longitudinal grooves wherein are housed ina freely slidable manner, noses projecting from said shaft to which saidnoses are solidly atfixed.

4-. The device according to claim 4, wherein said noses form an abutmentwith which an end wall of said groove coacts when the rod is thrust bysaid pressurized fluid to the maximum elongation position from saidbody, said noses providing another abutment with which the other end ofsaid groove interacts, when said rod is thrust by the pressurized fluidtowards the position of minimum elongation from said body, said rodcausing, when said abutments take place, the displacement of the shafton either side of said intermediate position.

5. The device according to claim 1, wherein said means for feeding apressurized fluid above and below said piston is respectively channelsformed in said body and respectively communicating with said cylindricalbore above and below said piston, said channels being connected to asource of pressurized fluid, and flow control means for said fluidflowing to said channels.

6. The device according to claim 1 including two axially spacedpre-loaded springs, a collar solidly afiixed to References Cited by theExaminer UNITED STATES PATENTS 5/1945 Mathys 7422 8/1953 Hirvonen 7422FRED C. MATTERN, JR., Primary Examiner.

F. E. BAKER, Assistant Examiner.

1. A DEVICE FOR CONTROLLING THE TRANSLATIONAL AND ROTATIONAL MOVEMENTSOF A ROD; COMPRISING A BODY HAVING A CYLINDRICAL STRAIGHTLINEAR BORE, AROD, A PISTON, SOLIDLY AFFIXED TO SAID ROD AND POSITIONED WITHIN SAIDBORE SO AS TO BE FREELY AND RECTILINEARLY DISPLACEABLE THERETHROUGH ANDROTATABLE ABOUT ITS OWN AXIS WITH RESPECT TO SAID BODY, SAID RODPROJECTING OUT OF SAID BODY, SEALTIGHT MEANS BETWEEN SAID BODY AND SAIDROD, AT THE POINT AT WHICH THE ROD PROJECTS FROM SAID BODY, A SHAFTHOUSED ALONG A CERTAIN PORTION OF ITS LENGTH WITHIN A CAVITY AXIALLYFORMED THROUGH SAID PISTON AND SAID ROD, SEALTIGHT MEANS BETWEEN SAIDSHAFT AND SAID ROD, MEANS FOR LOCKING SAID ROD AND SHAFT AGAINST MUTUALROTATION YET PERMITTING MUTUAL AXIAL DISPLACEMENTS THEREBETWEEN, MEANSFOR FEEDING A PRESSURIZED FLUID ABOVE AND BELOW SAID PISTON,RESPECTIVELY, MEANS FOR IMPARTING A ROTATIONAL DRIE TO SAID SHAFT, SAIDSHAFT PROJECTING FROM SAID BODY AT THE END REMOTE FROM THAT THROUGHWHICH SAID ROD PROJECTS, MEANS MOUNTING SAID SHAFT WITHIN SAID BODY SOAS FREELY TO MOVE IN AN AXIAL DIRECTION BY SMALL INCREMENTAL MOVEMENTSFROM AN INTERMEDIATE POSITION, AND ABUTMENTS COOPERABLE WITH SAIDCERTAIN PORTION OF SAID SHANK HOUSED WITHIN SAID CAVITY WHEN THRUST BYSAID PRESSURIZED FLUID TOWARDS THE MAXIMUM ELONGATION POSITION OR,RESPECTIVELY, TOWARDS THE MINIMUM ELONGATION POSITION WITH RESPECT TOSAID BODY.